In a package with a built-in millimeter wave antenna for an IC including a circuit for millimeter wave band (wavelength: 1 mm to 10 mm and frequency: 300 GHz to 30 GHz), considerations should be made on several points in terms of the structure in order to secure required characteristics (high frequency transmission characteristics, antenna directivity and the like) when designing the structure of the package. Although the details are given later, it is at least required that no material having a dielectric constant (adhesive, in particular), not to mention solder resist, should exist in the wiring portion on the package (on the surface side where the cap is provided for sealing).
An example of the technique related to the conventional art is described in Japanese Examined Patent Application Publication No. 7-46709. This document discloses a structure in which an electronic component (semiconductor element) is mounted in a recessed portion (cavity) provided on a base member (substrate) (for example, FIG. 3 and the relevant portions).
An adhesive is used for sealing a package including a semiconductor element and a transmission line for millimeter wave band or the like with a cap. Here, overflow of an adhesive from a cap adhesion portion needs to be suppressed by strictly controlling the amount of the adhesive to be used (application amount) in order to prevent the adhesive from adhering to an undesired portion such as a wiring portion. However, it is extremely difficult to perform control for suppressing such overflow of the adhesive.